Jasper Bryant-Greene wrote:
Hi guys
I'm about to embark on a project replacing a legacy single mail server running proprietary software with a cluster of Dovecot servers. We clearly need a shared mail store for these servers, but we are not happy with simply using a server running NFS as this becomes a single point of failure.
What have other people used? AFAICT our options are:
A shared block device (Fibre Channel, iSCSI, ATAoE etc) running GFS or similar to allow multiple servers to access it concurrently
Two or more NFS units, either with built-in support for replication of FS changes and failover, or with scripts for achieving this functionality
I prefer option 1, although it's expensive. What have other people used? Do we have other options?
I recommend a pair of NetApp filers (e.g. 2 x 3020c) exporting NFS from shared disk shelves in their high-availability mode. This is a hybrid of the two options, except a) it's a fully supported and stable NetApp configuration, b) they're sharing disk storage, c) you're not hog-tied to GFS, d) it's the best NFS implementation in the world (you can even trust the fcntl locking), e) it's really fast, f) NetApp's onboard snapshots and other funky software bits will make you wonder how you lived without them, g) the HA actually works.
I have a six-digit userbase with mailboxes in this configuration.
JG